Submission #255857

#	Time	Username	Problem	Language	Result	Execution time	Memory
255857		EntityIT	Travelling Merchant (APIO17_merchant)	C++14	100 / 100	129 ms	1528 KiB

merchant

#include <bits/stdc++.h>
using namespace std;

#define ALL(x) (x).begin(), (x).end()
#define SZ(x) static_cast<int>((x).size())

template<class T, size_t D>
struct vec : vector<vec<T, D - 1>> {
  template<class... Args>
  vec(size_t n = 0, Args... args)
      : vector<vec<T, D - 1>>(n, vec<T, D - 1>(args...)) {}
};
template<class T>
struct vec<T, 1> : vector<T> {
  template<class... Args>
  vec(Args... args)
      : vector<T>(args...) {}
};

template<class T>
inline bool Minimize(T& a, const T& b) { return a > b ? a = b, true : false; }
template<class T>
inline bool Maximize(T& a, const T& b) { return a < b ? a = b, true : false; }
inline int Next(int i, int n) { return i == n - 1 ? 0 : i + 1; }
inline int Prev(int i, int n) { return !i ? n - 1 : i - 1; }

mt19937 rng(static_cast<uint32_t>(chrono::steady_clock::now().time_since_epoch().count()));

constexpr int kSmallInf = 1e9;
constexpr int64_t kBigInf = 1e18;

int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);

  int n_vertices, n_edges, n_items; cin >> n_vertices >> n_edges >> n_items;

  vec<pair<int, int>, 2> price_items_vertices(n_vertices, n_items);
  for (auto& price_items : price_items_vertices) {
    for (auto& price_item : price_items) {
      cin >> price_item.first >> price_item.second;
    }
  }
  vec<int, 2> max_profit_pairs(n_vertices, n_vertices);
  for (int i = 0; i < n_vertices; ++i) {
    for (int j = 0; j < n_vertices; ++j) {
      for (int k = 0; k < n_items; ++k) {
        if (~price_items_vertices[i][k].first && ~price_items_vertices[j][k].second) {
          Maximize(max_profit_pairs[i][j], - price_items_vertices[i][k].first + price_items_vertices[j][k].second);
        }
      }
    }
  }

  vec<int, 2> min_distance_paths(n_vertices, n_vertices, kSmallInf);
  for (int u = 0; u < n_vertices; ++u) {
    min_distance_paths[u][u] = 0;
  }
  while (n_edges--) {
    int u, v, w; cin >> u >> v >> w; --u; --v;
    min_distance_paths[u][v] = w;
  }
  for (int k = 0; k < n_vertices; ++k) {
    for (int i = 0; i < n_vertices; ++i) {
      for (int j = 0; j < n_vertices; ++j) {
        Minimize(min_distance_paths[i][j], min_distance_paths[i][k] + min_distance_paths[k][j]);
      }
    }
  }

  auto Check = [&](int efficiency) -> bool {
    vec<int64_t, 2> f(n_vertices, n_vertices, -kBigInf);
    for (int i = 0; i < n_vertices; ++i) {
      for (int j = 0; j < n_vertices; ++j) {
        if (min_distance_paths[i][j] != kSmallInf && i != j) {
          f[i][j] = static_cast<int64_t>(max_profit_pairs[i][j]) - static_cast<int64_t>(efficiency) * min_distance_paths[i][j];
        }
      }
    }
    for (int k = 0; k < n_vertices; ++k) {
      for (int i = 0; i < n_vertices; ++i) {
        for (int j = 0; j < n_vertices; ++j) {
          Maximize(f[i][j], f[i][k] + f[k][j]);
        }
      }
      for (int i = 0; i < n_vertices; ++i) {
        if (f[i][i] >= 0) {
          return true;
        }
      }
    }
    return false;
  };

  int left_answer = 0, right_answer = static_cast<int>(1e9);
  while (left_answer < right_answer) {
    int middle_answer = (left_answer + right_answer + 1) >> 1;
    if (Check(middle_answer)) {
      left_answer = middle_answer;
    } else {
      right_answer = middle_answer - 1;
    }
  }

  cout << left_answer << '\n';

  return 0;
}

• Subtask 1: 12 / 12
• Subtask 2: 21 / 21
• Subtask 3: 33 / 33
• Subtask 4: 34 / 34